PLST-1 is needed for cytokinetic furrow formation, which requires concurrent recruitment of F-actin and myosin. (A) Time-lapse montages of equatorial segment of control and plst-1 zygotes coexpressing GFP::PLC1δ-PH and HIS-58::mCherry from anaphase onset to the completion of cytokinesis. For all subsequent analyses of plst-1 zygotes, measurements are only done on zygotes that are able to complete cytokinesis. (B) Quantification of time required from anaphase onset to the completion of cytokinesis in control (n = 18) and plst-1 (n = 29) zygotes. (C) Furrowing kinetics of the control (n = 13) and plst-1 (n = 20) zygotes from anaphase onset to the completion of cytokinesis. (D) Quantification of the furrow constriction rate from the normalized cortical distance of 0.75 to 0 (gray area in C) in control (n = 13) and plst-1 (n = 20) zygotes. (E) Time-lapse montages of cortical segment of the furrow region in control and plst-1 zygotes coexpressing GFP::Utrophin and NMY-2::mCherry from anaphase onset to complete ingression of the cortex from the imaged focal plane. (F) Normalized cortical fluorescence intensity profiles of GFP::Utrophin and NMY-2::mCherry in control (n = 16) and plst-1 (n = 18) zygotes from anaphase onset to complete ingression of the cortex from focal plane. Data are represented as mean ± SEM. ****, P < 0.0001; n.s., not significant; Mann–Whitney U test. Bars, 5 µm.